Making american cheese from heat treated milk

ABSTRACT

A method for making American cheese and similar types of cheese from heat treated milk so as to provide increased cheese flavor. In accordance with the method, a combination of a particular type of a proteolytic micrococcus and a particular type of lipase are added at specified levels to heat treated milk which is to be made into American cheese. A particular lactobacillus microorganism may also be used in connection with the combination of the indicated proteolytic micrococcus and specified lipase to provide improved body, flavor and/or texture to the cheese.

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Roberts 1451 ar. 21, 1972 [541 MAKlNG AMERICAN CHEESE FROM 2,793,1225/1957 Erekson ..99/1 16 HEAT TREATED MILK OTHER PUBLICATIONS Alford etal., Journal of Dairy Science, Vol. 33, 1950 (pp. 107,112,113 & 115-119)SF221J8.

Primary Examiner-Lionel M. Shapiro Assistant Examiner-D. M. NaffAttorney-F itch, Even, Tabin & Luedeka [5 7] ABSTRACT A method formaking American cheese and similar types of cheese from heat treatedmilk so as to provide increased cheese flavor. In accordance with themethod, a combination of a particular type of a proteolytic micrococcusand a particular type of lipase are added at specified levels to heattreated milk which is to be made into American cheese. A particularlactobacillus micro-organism may also be used in connection with thecombination of the indicated proteolytic micrococcus and specifiedlipase to provide improved body, flavor and/or texture to the cheese,

13 Claims, No Drawings MAKING AMERICAN CHEESE FROM HEAT TREATED MILKThis application is a continuation-in-part application of my copendingapplication Ser. No. 668,681, filed Sept. 18, 1967 and entitled Methodof Making American Cheese from Heat Treated Milk, which earlier filedapplication is now abandoned.

The present invention relates generally to a method of making cheesefrom heat treated milk and more particularly relates to a method formaking American cheese and similar types of cheese, with improvedflavor, from pasteurized milk.

The term heat treated milk, as used in this specification, refers to amilk which is subjected to heat treatment at least equivalent to heatingthe milk to 135 F. and cooling it down with no-hold at the temperature.The heat treated milk may be pasteurized, which is generally understoodto mean that the milk tests phosphitase negative, or may be sterilized,which is generally understood to mean that the micro-organisms andenzymes are substantially or completely destroyed. As used in the cheeseart, heat-treated (differentiated with a hyphen in this specification)milk is milk which has been heated to from 135 to 150 F. and cooled withno-hold. Such treatment generally destroys gas forming micro-organismsbut is less than pasteurizing conditions and such treatment may bereferred to herein as sub-pasteurizing.

American cheese, as used herein, is a term which identifies a group ofcheeses which includes Cheddar cheese and Colby cheese and furtherincludes Monterey and Jack cheeses. Cheddar cheese derives its name froma step in the manufacturing process wherein the drained cheese curd ischeddared or matted. While the present invention is sometimes describedwith particular reference to Cheddar cheese, it should be understoodthat the invention is applicable to cheese having similar curdcharacteristics, texture, and flavor, such as granular or stirred-curdcheese and washed-or soaked-curd cheese.

American cheese generally is a hard cheese, ranging in color from nearlywhite to a more traditional red-yellow color and is made from whole cowsmilk. Many attempts have been made to make American cheese fromheat-treated subpasteurized or pasteurized milk, and considerableresearch has been conducted in respect of American cheese made fromheat-treated and pasteurized milk. For example, such technique isreported in the following articles: Cheddar Cheese from PasteurizedMilk, Price, Journal of Dairy Science, Vol.

10, pp. 155-168 (1927); A Comparison of Three Methods of PasteurizingMilk for Cheddar Cheese Making, Price and Prickett, Journal of DairyScience, Vol. 11, pp. 69-78 (1928); Bacteriology of Cheese, 1. Effect ofPasteurizing the Milk on the Nitrogenous Decomposition of CheddarCheese, Lane and Hammer, Iowa State College Research Bulletin No. 183(1935); Occurrence of Micrococci in Cheddar Cheese Made from Raw andfrom Pasteurizied Milk, Alford and Frazier, Journal of Dairy Science,Vol. 33, pp. 107-114 (1950); Enhancement of the Flavor of Cheddar Cheeseby Adding a Strain of Micrococcus to the Milk, Robertson and Perry,Journal of Dairy Research, Vol. 28, pp. 245-252 (1961). It has also beenknown to increase the flavor of certain cheese by the use of enzymes ashas been disclosed in US. Pat. No. 2,531,329. However, none of theseprior references has provided a satisfactory disclosure for providingAmerican cheese and similar types of cheese for commercial purposes and,prior to this invention, the use of pasteurized milk in the manufactureof American cheese had no commercial significance.

When Cheddar cheese, in particular, is made from heattreated milk it isusually produced by a so-called, timeschedule" method. Use of thetime-schedule method makes it possible to control the amount of acidthat develops and the rate of acid development during the makeprocedure.

in accordance with known methods for making American cheese and similartypes of cheese from sub-pasteurized milk, the milk is cooled after heattreatment to at least the setting temperature of from 86 to 88 F. and isrun into a cheese vat.

A starter of Streptococcus lactis is added and the milk is stirred,usually for about an hour as the milk develops acidity through bacterialaction and this is known as ripening. The amount of starter is adjustedso that acid will develop at a desired rate during the make procedureand the time in the vat is controlled accordingly. Rennet and color, ifdesired, are mixed thoroughly into the ripened milk and stirring isstopped. The milk is permitted to set, i.e., form a coagulum of curd.When the curd is sufficiently firm, usually about thirty minutes aftersetting, it is cut with curd knives into cubes. it is then stirredcontinuously from the time of cutting until the whey is drained from thecurd. After cutting, the curd is heated gradually over a period of about30 minutes to a temperature of about F.

The whey is drained after heating. The curd is then packed about 7 or 8inches deep on each side. When the curd is firm enough to be turnedwithout breaking, it is cheddared. That is, it is cut into slabs 5 or 6inches wide which are turned frequently, and when firm enough, piledinto layers. After cheddarring, the curd is then run through a curd milland is spread over the bottom of the vat and stirred. Salt is mixed inand the curd is piled on either side of the vat while additional wheydrains.

After salting and draining, the curd is transferred to cloth lined metalhoops and is pressed for about 30 minutes. The cheese is dressed and ispressed again for 12 to 24 hours. The cheese is then removed from thehoops, wrapped in a suitable material, and cured for a desired period,usually at least 60 days, sometimes for 3 to 6 months, and in someinstances for a year or longer.

The above-described method is for producing Cheddar cheese fromheat-treated or sub-pasteurized milk. However, the Cheddar cheeseproduced from heat-treated milk often lacks the flavorcharacteristically associated with Cheddar cheese produced from rawmilk. The problem of flavor development becomes more difficult withpasteurized milk, i.e., as heat treatment is increased. it would bedesirable to provide a method for producing American cheese and similartype cheese from heat-treated milk, pasteurized milk and milks havinghigher heat treatments with an improved American cheese flavor.

It is well known that heat treatment of milk destroys desirablemicro-organisms and enzymes, as well as undesirable micro-organisms andenzymes. Various attempts have been made, as indicated in theaforementioned references, to provide desirable ripening agents forheat-treated and pasteurized milk so as to produce improved flavor incheese made from heat treated milks. However, these attempts have notproduced a cheese with an improved American cheese flavor suitable forcommercial purposes.

Current cheese making practices involving accelerated aging or curingtechniques particularly need the destruction of undesirablemicroorganisms and enzymes in raw milk and even in heat-treated milk.The presence of undesirable microorganisms can be accentuated with rapidcuring of cheese thereby providing bad cheese. Accordingly, the need fordestroying undesirable micro-organisms and enzymes in the manufacture ofAmerican cheese and similar types cheeses is even greater today.

It is an object of the present invention to provide an improved methodfor making American cheese and similar type cheese from heat treatedmilks. It is another object of the present invention to provide a methodfor making such cheese with increased flavor from heat treated milks. Itis a further object of the invention to provide a method for makingAmerican cheese and similar type cheese from pasteurized milk and milkgiven higher heat treatments to provide cheese of improved flavor andbody from such milks. Another object of the invention is to provide animproved method for making American cheese and similar type cheese withaccelerated aging or curing.

These and other objects of the present invention will become more clearfrom the following detailed disclosure.

It has been found, in accordance with various of the features of thepresent invention, that a combination of a particular proteolyticmicrococcus and a particular lipase, used at specified levels ofaddition to milk, given previous heat treatment, produces an Americancheese with a higher cheese flavor and can provide a flavor equivalentto that obtained in American cheese produced from raw milk.

The proteolytic micrococcus is a particular micro-organism whichprovides controlled milk protein breakdown during curing of the cheese.However, the protein breakdown during curing of the cheese should not beso great as to produce a bitter flavor from too extensive breakdown ofthe milk protein. That is, the proteolytic activity of the proteolyticmicrococcus should produce only a desired level of protein breakdowninto amino acids, peptides and other related protein fragments.

The desired proteolytic micrococcus for the process of this invention isa Micrococcus Cohn selected from Subgroups l to 4, inclusive. Theclassification of Micrococcus Cohn and the manner of determination ofthe Subgroups is reported in Identification Methods for Micrabiologists,Gibbs and Skinner 1966). The relative characteristics of MicrococcusCohn Subgroups through 4 are set forth in the following table:

r =variahle Thus, the proteolytic micrococcus to be used in accord withthis invention will be acetoin positive and convert glucose to acidunder aerobic conditions. It has been found that more preferred resultsare achieved with micro-organisms from Mierococcur (o/m Subgroup 2 andeven more preferred results are obtained when the Micrococcus Cohn werefrom micro-organisms of Subgroup 2 which were obtained from raw milk.

It has been found that micro-organisms from Micrococcus Cohn Subgroups 5through 8, inclusive, are not satisfactory for the production of thedesired flavor in American cheese and similar types of cheese.Micro-organisms in these Subgroups 5 to 8, inclusive, are acetoinnegative and some in these Subgroups are weak or negative in convertingglucose to acid under aerobic conditions.

A preferred proteolytic micrococcus is a proteolytic micrococcusobtained from the University of Wisconsin and designated T-3. Thecultural and biochemical characteristics of T-3 micrococcus are asfollows:

Catalase Gram stain cocci in groups Acid from glucose:

aerobic anaerobic Coagultise Phosphatase Aceloin Acid from:

arabinose lactose maltose mannitol Baird-Parker Classification: Group llMicrocor'cru' Colin Subgroup 2 Additional tests:

Gelatin, liquefied slow) Growth, pH 4.2

9.6 Litmus milk (86 F.)

Acid (pink) Dye reduction (white) Coagulation Nitrate Reduction Acidfrom:

cellobiose dextrin glycerol inositol inulin levulose (d-fructose)mannose melezitose melibiose rafl'inose rhamnose salicin sorbitolsucrose trehalose xylose Thermal death time:

l6lF./l5 sec. I61 F./26 sec. l6l F./28 sec. F./l5 sec. Recovery fromcheese: (XlO-l gram) After starter 33 After ripening l0 After cutting270 After heating 1300 After cheddaring 3000 After sailing 2100 After 24hrs. 93.5 After 1 wk. 66.8 After 2 wks. 3.5 After 4 wks. 0.92 After 9wks. 0.34 After 12 Wks. 0.62 After 4 months After 5 months After 6months After lOVi It has been found that when the Micrococcus CohnSubgroups 1 to 4, inclusive, micro-organisms are added in themanufacture of American cheese from pasteurized milk there is a clearcontribution to the cheese flavor as compared to the flavor produced incheese from pasteurized milk without the addition of thesemicro-organisms. It has also been found that this improvement isnoticeable under accelerated curing conditions.

The proteolytic micrococcus may be added to the heat treated milk as aculture or may be formed into a concentrated bacterial cell paste priorto addition.

Proteolysis of the milk protein in the cheese, to provide the desiredbreakdown of protein, occurs primarily during curing of the cheese curd.The amount of proteolysis is related to the level and type ofmicro-organisms present during curing, as well as the curing conditions.Growth of the micrococcus is slowed after addition ofthe S. laclisstarter culture to the milk due to the formation of lactic acid and thelevel of the micrococcus is determined primarily by the level ofaddition to the milk.

While not wishing to be bound by any theory, it is believed that themicrococcus continues to grow slowly under the acidic conditions presentduring curing of the cheese. ln this connection, it is further believedthat the proteolytic activity of the micrococcus is primarily due toproducts produced by and during the growth of the micrococcus. It isbelieved that a produce so produced acts to break down the protein to adesired level and does not continue to break down protein to undesiredby-products. In other words, the system seems to be self-limiting as tothe proteolytic activity.

The proteolytic micrococcus of the invention, as described above, isdesirably added at levels so as to provide from about 1 X to about 1 X10 preferably l X 10 cells per pound of milk at the time of addition ofthe starter culture. This level of micrococcus may be established byadding a relatively low level of viable micrococcus and allowing arelatively long period of time for growth of the micrococcus prior toaddition of the starter culture. However, growth of the micrococcusduring long periods of time is somewhat unpredictable and it isgenerally preferred to limit the period of time after addition of themicrococcus and prior to addition of the starter culture to about onehour or less. During such relatively short periods of time themicrococcus primarily undergoes an adjustment to the milk environmentand little growth occurs.

The level of addition of the micrococcus is, of course, dependent on thetime allowed for growth. For example, to achieve the preferred range ofcells per pound of milk of the micrococcus for a growth period of lessthan about one hour requires the addition of from about 0.1 percent toabout 0.5 percent by weight of the milk of a liquid culture containingabout 2.0 X 10 cells of viable micrococcus per milliliter. Such level ofaddition of viable micrococcus may also be accomplished by adding asmaller amount of a cell paste of the micrococcus. When the proteolyticmicrococcus described above is used along with heat treated milk, thereis a tendency to produce undesired flavor. However, it has been found,in accordance with the present invention, that the use of the particularproteolytic micrococcus in combination with a specified lipase producesa desirable American cheese flavor. The lipase will be an enzyme whichsplits fat into fatty acids and glycerol. In this connection, it isdesirable to add a lipase of a type and at a level such that the fat isselectively split into fatty acids and glycerol. The lipase should beadded in sufficient amount to contribute to the flavor but should not beadded at such a high level as to provide a rancid flavor. At levels ofaddition of the particular lipase above about 2 grams of dry powderedenzyme preparation per 1,000 pounds of milk, a rancid flavor may beproduced. At levels of addition below about 0.1 grams per 1,000 poundsof milk that is little flavor contribution from the particular lipase,and an undesired flavor may be produced by the proteolytic micrococcus.The lipase is preferably added at a level of 0.25 grams per 1,000 poundsof milk.

The particular lipase for use in the practice of this invention is thatobtained by extraction from the throat tissue of calves. Other suitablelipase may be obtained by extraction from the throat tissue of lambs orkids. These enzymes are commercially available and their manufacture isgenerally disclosed in US. Pat. Nos. 2,531,329 and 2,794,743. Theseparticular lipases, while known for use in cheese manufacture, worksynergistically with the particular micrococcus micro-organisms of theinvention to provide the desired curing of American cheese and theresultant flavor. Other enzymes than those specified herein do not givecheese of desired flavor. The lipases contemplated herein areself-limiting in the hydrolysis of milk fat and do not break down suchfat to undesired end products. Such lipases will be referred to hereinas self-limiting lipases to denote their restricted hydrolizingactivity.

When American cheese or similar type cheese is produced from heattreated milk, to which the above described combination of a proteolyticmicrococcus and the lipase is added,

the cheese has a desirable Cheddar cheese flavor. However, the body andtexture of the cheese may be soft or crumbly or otherwise undesirablefrom some purposes. It has further been found that an improved body andtexture can be provided when a lactobacillus or a closely relatedmicro-organism is also added to the heat-treated milk prior to settingof the milk. Such a lactobacillus may be referred to as a bodyingmicro-organism. Addition of such a micro-organism is optional, but maybe used where a particular body or texture is desired. Some of suchlactobacillus micro-organisms also provide flavor to the cheese. Varioushomofermentative lactobacilli may be used, such as lactobacillus lactisand Lactobacillus bulagricus. The preferred lactobacillus micro-orgamismis a strain of L. lactis. The lactobacillus micro-orgamism will usuallyhave some proteolytic activity and may contribute some flavor toheat-treated milk used to make cheese in accordance with the describedmethod. The preferred lactobacillus micro-organisms will develop from1.0 to 2.0 percent acid in milk. However, as previously stated, thelactobacillus micro-organism is primarily used when it is desired toprovide particular body and texture characteristics.

The preferred micro-organism is known as Lb, and it has been identifiedas ATCC 7995. This micro-organism exhibits the followingcharacteristics:

Temperature for growth 55 C. Microscopic Evaluation Granules ColonyAppearance NH from Arginine Lipolytic (Spirit Blue) Catalase LitmusMilk: Acid Dye Reduct. Coagulation Acid in Milk Acid from: GalactoseGlucose Lactose Maltose Mannitol Salicin Sorbilol Sucrose Trehalose Whenused, the lactobacillus or closely related micro-organism, is added as amilk culture or the micro-organism. The milk culture is obtained byadding the lactobacillus micro-organism to a suitable substrate andpermitting growth of the micro-organism to proceed until an equivalentlactic acid acidity of 1.0 percent to 2.0 percent is obtained. The milkculture of the lactobacillus micro-organism is then added to the heattreated milk which is to be made into cheese at a level of from about0.1 to about 0.3 percent by weight of the milk. At levels above thestated range, an undesired flavor is sometimes detected. At levels belowthe stated range, there is little contribution to the body or texture ofthe cheese produced from the heat treated milk.

As stated above, the flavor contribution from the proteolyticmicrococcus may be due to an enzymatic reaction wherein an enzyme isproduced as a product by the micrococcus during curing of the cheese. Inanother embodiment of the present invention, such enzyme may beextracted from a proteolytic micrococcus culture prior to treatment ofthe heat treated milk to produce cheese. For this embodiment, theextracted enzyme is added directly to the milk which has been heattreated and before setting of the milk. It is added at a levelequivalent to that which would be provided by the proteolyticmicrococcus if present.

- Various tests have been specified in the foregoing. These tests aregenerally standard and recognized tests so that this specification hasnot been elaborated with details as to test procedures.

The following examples further illustrate various features of thepresent invention but are intended in no way to limit the scope of theinvention which is defined in the appended claims.

EXAMPLE I Twenty-five thousand pounds of raw milk was heat treated at atemperature of 162 F. for a period of 16 seconds to effectpasteurization thereof. The milk was pumped to a vat and al lowed tocool to 88 F. To the cooled, heat-treated milk as added 50 pounds of amilk starter culture including a proteolytic micrococcus. The culturecontained 1.75 X cells per gram of a proteolytic micrococcus. Theproteolytic micrococcus culture was one which had been obtained from theUniversity of Wisconsin, designated as T-3. To the milk was also added6.25 grams of a lipase which had been obtained by extraction from thethroat tissue ofa calf. After addition ofthe above culture and thelipase enzyme, 250 pounds of a Streptococcus lactis starter culture wasalso added to the milk.

The milk was agitated and allowed to ripen for a period of one hour.Seventy-five ounces of a rennet solution were then mixed into theripened milk, and the stirring was stopped. After about minutes the curdwas sufficiently firm to cut and was cut with curd knives intoquarter-inch cubes. Stirring was then commenced and was continued untilthe whey was drained. Draining was completed in about 30 minutes, andthereafter the curd was packed in a layer about 7 or 8 inches deep oneach side. When the curd was firm enough to be turned without breaking,it was cheddared. The curd was then run through a curd mill and wasspread evenly over the bottom of a vat and stirred. Three pounds of saltfor each one thousand pounds of milk were then mixed in and the curd waspiled on each side of the vat while additional whey was drained.

After salting, the curd was transferred to cloth-lined metal hoops, andwas pressed, dried and wrapped in a plastic film in accordance withconventional procedures.

After wrapping, the cheese was stored in a warehouse at a temperature ofF. to effect curing. The cheese was cured for a period of 6 months. Atintervals of2 months a sample of the cheese was removed and inspected.

The samples of cheese which had been prepared in accordance with theabove procedure were compared with samples of cheese which had beenprepared in a similar manner from the same milk with the exception thatthe combination of a proteolytic micrococcus and a lipase enzyme of thepresent invention was not added to the heat-treated milk prior tosetting. In all cases, the samples of cheese produced by the abovedescribed method of the invention were scored considerably higher inflavor than the control samples. The body and texture of the cheeseproduced by the above method was acceptable.

EXAMPLE ll Heat-treated milk was prepared for use in making Cheddarcheese in accordance with the procedure of Example I with the exceptionthat pounds ofa liquid milk culture of L. lactis was also added to theheat-treated milk prior to setting of the milk. The L. lactis milkculture was prepared by introducing a stock culture into skim milk andpermitting growth to proceed until an acidity of 1.6 percent equivalentlactic acid was reached. The L. lactis stock culture was a strainobtained from the USDA. and designated Lb, (ATCC 7995). Cheddar cheesewas then produced in accordance with the procedure of Example I. Samplesof Cheddar cheese prepared in accordance with the above procedure werecompared with sames of Cheddar cheese which had been prepared in asimilar manner from the same heat-treated milk but without the additionof the micrococcus, L. lactis, or enzyme of the present invention. Inall cases the samples of cheese produced by the above method were scoredconsiderably higher in flavor than the control samples and were scoredequal or better in body and texture.

EXAMPLE lll A cell paste of the proteolytic micrococcus used in Examplesl and II was prepared by the following procedure: 200 milliliters ofaviable culture of the proteolytic micrococcus was added to 30 liters ofsterilized medium of the following composition to provide an inoculum.

The inoculum was incubated for two days at 86 F. to provide a culture ofthe proteolytic micrococcus. The culture was then transferred to anadditional 600 liters of sterile media of the same composition aspreviously described and incubation was continued for 2 days at 86 F.

The culture was then centrifuged to provide 2,600 grams of concentratedcell paste containing 121 X 10 viable cells of proteolytic micrococcusper gram.

Cheddar cheese was then made in accordance with the procedure of Examplell with the exception that eight grams of the proteolytic micrococcuscell paste were used per 1,000 pounds of milk instead of a culture ofthe proteolytic microccus. The Cheddar cheese was comparable in everyrespect with the Cheddar cheese produced by the method of Example ll.

EXAMPLE lV Cheddar cheese was prepared in accordance with Example [Iexcept that the proteolytic micrococcus was another organism than T-3but was a Micrococcus Cohn from Subgroup 2 derived from raw milk. Theresulting cheese was substantially better than the control which wasmade by the same procedure except that the Microccacus Cohnmicro-organisms were omitted.

EXAMPLE V Cheddar cheese was prepared in accordance with Example llexcept that the proteolytic micrococcus was a Micrococcus Cohn fromSubgroup 2 derived from pasteurized milk. The resulting cheese did notscore as well as the cheese of Examples II and IV but were better thancontrol described in Example IV.

The American cheese from pasteurized milk can be slow cured or fastcured with the added micro-organisms and enzyme. When such cheese ismade from raw milk, undesired micro-organisms frequently develop to suchdegree as to provide unwanted flavors and bad cheese. The ability toaccelerate curing with more uniform cheese resulting is a markedadvantage of the invention.

From the above it can be seen that the described method providesAmerican cheese from heat treated milk with improved flavor and withgood body and texture.

I claim:

1. A method for producing American cheese from heat treated milk whereinthe milk is inoculated with a lactic acid producing culture and isthereafter set, which comprises adding prior to curing of the cheese aproteolytic micrococcus selected from Micrococcus Cohn subgroups, l, 2,3, and 4, a self-limiting lipase, and a lactobacillus bodyingmicro-organlSm.

2. The method for producing American cheese from heat treated milk ofclaim 1, wherein the proteolytic micrococcus and the lipase are added tothe milk prior to setting of the milk.

3. The method for producing American cheese in accordance with claim 1wherein the heat treatment effects pasteurization of the milk.

4. The method in accordance with claim 1 wherein the proteolyticmicrococcus is from Micrococcus Cohn Subgroup 2.

5. The method in accordance with claim 1 wherein the proteolyticmicrococcus is T-3.

6. The method in accordance with claim 2 wherein the proteolyticmicrococcus is added at a level of between about 1x 1 O to about 1X 10cells per pound of milk.

7. The method in accordance with claim 6 wherein the level ofproteolytic micrococcus is about 1x10 cells per pound of milk.

8. The method of claim 2 wherein the lipase is added at a levelsufficient to contribute flavor and at a level below which a rancidflavor occurs.

9. The method of claim 8 wherein the lipase is added at a level betweenabout 0.1 grams per 1,000 pounds of milk and about 2 grams per 1,000pounds of milk.

10. The method of claim 9 wherein the lipase is added at a level ofabout 0.259 grams per 1,000 pounds of milk.

11. The method of claim 1 wherein the bodying micro-organism is alactobacillus lactis or a lactobacillus bulgan'cus.

12. The method of claim 1 in which the bodying organism is alactobacillus which develops from 1.0 to 2.0 percent acid in milk.

13. The method of claim 11 wherein the micro-organism is lactobacilluslactis and develops from 1.0 to 2.0 percent acid in milk.

2. The method for producing American cheese from heat treated milk ofclaim 1, wherein the proteolytic micrococcus and the lipase are added tothe milk prior to setting of the milk.
 3. The method for producingAmerican cheese in accordance with claim 1 wherein the heat treatmenteffects pasteurization of the milk.
 4. The method in accordance withclaim 1 wherein the proteolytic micrococcus is from Micrococcus CohnSubgroup
 2. 5. The method in accordance with claim 1 wherein theproteolytic micrococcus is T-3.
 6. The method in accordance with claim 2wherein the proteolytic micrococcus is added at a level of between about1 X 107 to about 1 X 1010 cells per pound of milk.
 7. The method inaccordance with claim 6 wherein the level of proteolytic micrococcus isabout 1 X 109 cells per pound of milk.
 8. The method of claim 2 whereinthe lipase is added at a level sufficient to contribute flavor and at alevel below which a rancid flavor occurs.
 9. The method of claim 8wherein the lipase is added at a level between about 0.1 grams per 1,000pounds of milk and about 2 grams per 1,000 pounds of milk.
 10. Themethod of claim 9 wherein the lipase is added at a level of about 0.259grams per 1,000 pounds of milk.
 11. The method of claim 1 wherein thebodying micro-organism is a lactobacillus lactis or a lactobacillusbulgaricus.
 12. The method of claim 1 in which the bodying organism is alactobacillus which develops from 1.0 to 2.0 percent acid in milk. 13.The method of claim 11 wherein the micro-oRganism is lactobacilluslactis and develops from 1.0 to 2.0 percent acid in milk.